set_timeout ?reset f sets the timeout value for future Comet connections
to f. If reset is true then current connections are closed and the
new timeout value will apply to the reopened connections. Default value
for reset is false.

valdeactivate:unit -> unit

deactivate () ceases all Comet related activity. Each opened connection
is closed. Further attempts to connect to the server with a Comet specific
content type will result in a HTTP status code 503 (Unavailable).
If called when Comet is not activated it does nothing (not even logging
the deactivation attempt.

valactivate:unit -> unit

activate () starts serving Comet requests. It is the client's own
responsibility to reopen a connection. If Comet was already activated it
keeps going and nothing happens.

valactivated:unit -> bool

activated () reflects the activation state of the Comet
module. If false it indicates that Comet connections are answered with a
HTTP status code 503. If true it indicates that Comet connections are
handled in a standard fashion by the server.